The recording career that Willie Nelson began in the early 1960s had pretty much petered out by the early '70s, following some minor successes. By 1972, he had become so disgusted with the country music industry and his place in it that he exited the Nashville scene entirely, going into "retirement" in Austin. But it didn't take long for the freaky, freewheeling, hippie-era spirit that had emerged there -- personified by artists like former Sir Douglas Quintet frontman Doug Sahm -- to infect and inspire Willie, who soon started over with a whole new approach.

Before long, Willie became the first country artist ever to sign to Atlantic Records, and in 1973 he unveiled his first album for the label, Shotgun Willie. This revolutionary record marked not only Nelson's first real step toward fame (though it would take a while), but also a huge leap forward for country music. For starters, eschewing the effective-but-polite production that typified his RCA output, Willie made a more visceral connection to his real, raw country roots. The Texan tapped into his love of Western swing to record loose-limbed takes on two Bob Wills tunes: "Stay All Night (Stay a Little Longer)" and "Bubbles in My Beer." He also covered his San Antonio contemporary Johnny Bush's hardcore honky-tonker "Whiskey River."

Another longhorn pal, Waylon Jennings, was already working out his own variation of the "outlaw country" template that would soon turn Nashville upside down. (The pair would make their place in history as the iconoclastic style's avatars.) Jennings' pioneering Lonesome, On'ry and Mean album was already in the can by the time work began on Shotgun Willie; Jennings took the earliest outlaw steps, so it was only natural for him to add some guitar and vocals to his buddy's 1973 declaration of independence. Likewise, Doug Sahm not only contributed his own guitar and voice to Shotgun Willie, but also stood as an early model for the possibilities of combining country and R&B influences.

Of course, Atlantic was known as the home of R&B, a fact clearly not lost on Willie. It was obvious from the opening moments of the album, with the title track's horn-punctuated soul flavor, that the Memphis-born Stax sides Atlantic helped distribute had a place in Nelson's musical mindset at the time. Wayne Jackson and Andrew Love, aka The Memphis Horns, were part of the Memphis R&B mafia, contributing to classics by everyone from Wilson Pickett to Otis Redding, and they put some serious soul power behind Willie.

Besides Shotgun Willie's blend of country, soul and rock 'n' roll, the most crucial element of its let-it-all-hang-out feel was the kind of communal vibe that had helped revitalize Nelson in Austin. Rather than continue to rely on a revolving door of Nashville session players from album to album, he built his own band from scratch; not for nothing did he dub them The Family. Their organic, all-for-one modus operandi was partly inspired by Joe Cocker's Mad Dogs & Englishmen, that big and brotherly band led by Leon Russell (the latter's "You Look Like the Devil" and "A Song For You" top off Shotgun Willie's list of covers), and partly by Delaney & Bonnie's country-soul band (where Russell shared space with Eric Clapton.

Here's an album guide and playlist tracking the evolution of a country classic.